Yes, personal computing is 30 years old. The IBM 5150 was launched in August 1981. It wasn’t the first self-contained desktop computer: IBM had been producing them since the mid 1970’s. This one, however, was much cheaper and it sold by the bucketload.

The idea of devolving control of computers to the actual user of the data seemed quite revolutionary. I was in Marketing Management at the time and it was the realisation that I could soon be using a computer to provide me with marketing information derived from sales information, customer information and so forth, that led me off to Manchester to study Systems Analysis and Design. Not everyone bought into the idea so quickly, though. For a long time there were a lot of managers (male) who wouldn’t touch a computer on their desk as they associated them with typewriters and typewriters, of course, were used by (female) secretaries and not by (male) managers. At this time I think everyone thought of the PC as something for business users. The home computer user hadn’t really been invented yet. Lots of people had BBC and Sinclair computers, but these were thought of as games machines and “educational tools”.

You can’t tell by looking at it but the IBM 5150 weighed a ton. The screen, the monitor, and the keyboard were all extremely solid and heavy. No colour, no internet, no USB ports, no music, no Windows, not even a mouse. Even then, though, we had word processing (eg WordStar and WordPerfect), spreadsheets (eg Supercalc and Lotus 1-2-3), and database systems (eg dBase and others). I spent my first years in computing developing database applications using a program called Everyman.

Note the twin floppy disc drives on the photograph. The 5.25 inch removable and changeable floppy discs that went into these drives had to hold everything – operating system, programs, and data. Some machines only had one floppy drive – and the earliest discs only had a capacity of 160kb.

The “operating system” is the programming that controls the actual programs and data, and makes it all play nicely with the physical hardware. The most common operating system in those days was “MS-DOS”. IBM did a deal with the creators of “MS-DOS” (Microsoft) to use their own version of this (called “PC-DOS”) in IBM personal computers. The operating system designated the floppy drives as “a:” and “b:”. When hard drives came along the operating system – naturally – used “c:” as the letter to designate the hard drive. Life’s got a lot more complicated since then but almost all Windows computers still use “c:” to designate the first (or only) hard drive and then other devices (such as DVD drives, USB pen drives) are allocated letters further down the alphabet.

A single jpg photo from a modern but ordinary 7 mega-pixel camera is probably going to be about 1.8mb in size (say, 2000kb). Therefore, one single photo from an average digital camera in 2011 is about 5-6 times the size of the entire disc space available to the first PCs (which may have had to contain, remember,the operating system, the program and the data all on one disc).

My own first proper computer (let’s not count my Sinclair ZX81 – great fun and very instructive but no business tool) was an Olivetti M21. This was designated as a “transportable” because the screen and system unit were integral and the keyboard clipped to the front. I had a mid-engined Fiat X1.9 at the time and the Olivetti would just – but only just – fit in the luggage space under the bonnet so that I could carry it around for onsite computer support. There wasn’t any room left to carry anything else. If I had a passenger they had to nurse my briefcase on their lap. I did try to carry the M21 on the tube once or twice, and that probably explains why my knuckles now hang rather close to the ground. Officially called a “transportable” computer, it was more often known as a “luggable”. At 15kg, it weighed about as much as 6 or 7 modern 15inch laptops – and you also had to carry boxes of floppies, the mains cable and adaptor, manuals etc. All this and no internet! I can’t imagine that in those days I ever thought of possibilities like remote computer support, but I do remember having a modem and some sort of online connection as far back as about 1984 or 1985.

Completely gratuitous picture of a Fiat X1.9

The screen on the Olivetti M21 was just 9 inches across the diagonal (as all screens are measured). The whole machine measured 40 x 32 x 10 cm. Like the IBM 5150, my M21 started off with twin floppy drives (but we had, at least, progressed to 360kb discs by then). It was a huge milestone in my computer consultancy career when I bought a hard drive from a client when we upgraded him to a bigger drive on his Olivetti M24. We still argue about just how big those drives were, but they were either 5mb upgraded to 10mb or 10mb to 20mb. A good, big drive today is 2 terabytes (approx 2,000,000 mbytes) so a modern drive is 100,000 times the size of a drive from 1984.

My M21 cost about £2000 in 1983 or 1984. Together with a printer (a Panasonic dot-matrix) and some essential software, my first “system” came to about £3000. That’s about £8000 in today’s terms. Hmm, maybe that iPad wouldn’t be such an expensive luxury after all.